This invention relates to a method of making a composite product from particles of an exfoliated vermiculite impregnated with a suitable impregnating composition containing a thermosetting resin, and to the composite product so produced.
Examples of decorative resinous composites in common use include "cultured" marble made from filled and pigmented polyester resin systems where colour blending is incomplete and which are cast using, vibration.
Granitic composites are made by dyeing or pre-pigmenting a polyester resin system, polymerising the resin, milling it to acceptable particle size and then using this to fill a liquid unsaturated polyester resin system which is either clear or which has been dyed, and in which the pre-coloured set polyester resin particles do not either float or drop out during the subsequent casting or spraying of the product.
A further composite is produced when pre-pigmented resin systems are applied through a multi-head gun onto substrates in such a way that a variegated finish results, due to the incomplete mixing or blending of the different colour streams on the surface.
All three composites described above are characterised by high cost because the resin proportion of the final composite generally exceeds 80% by weight. Another disadvantage of most composites is that a slurry or a paste or a composition containing hard particles such as stone or marble chip cannot be press formed. In addition, resinous compositions heavily filled with inorganic extenders such as calcium carbonate cannot be easily cut or worked after casting and may often be dimensionally unstable.